Mars Snooper

[masterblaster]

My Mars Snooper that I just built and launched once is now needing some fixing
I would like to know if anyone can give me some good ideas on what to do here. If you can see the attached pictures there is a tiny crack at the base of the fin in addition to the broken landing gear. I am debating on taking the entire fin off and replacing it, or seeing if there are better options
.

[Marc_G]

IF the original glue bond is wood to cardboard/paper with wood glue or white glue, then the best thing is just to bend the fin back a bit to open up the crack a bit, and use whatever method works for you to squeeze more glue in there. Then get the fin back into position and tape or clamp it into place. Wipe off excess glue, allow to dry overnight before doing anything else. This should restore it to pretty much original strength.

Avoid ripping it off, as it is less likely you will get it positioned exactly where it should be.

I've got a Mars Snooper in my build pile. The BMS clone. Where did yours come from?

Marc

[C-57D]

When I get hairline cracks, I just wick some thin CA glue in there, problem fixed.

[Marc_G]

When I get hairline cracks, I just wick some thin CA glue in there, problem fixed.

I've done this with good results on some rockets, but I find the CA to existing wood/white glue and or paper/cardboard tends not to be as strong as the original glue joint. The Snooper tends to put these joints under stress during landing due to the design of the thing, so I recommend against the CA process here, under the assumption the original joint is white/wood glue.

[Micromeister]

Marc_G is right on: CA becomes very brittle shortly after drying. A much better bond can be obtained by working white glue into the cracks and paper/cardboard/wood joints. once dry these repairs will be stronger then the wood/paper they are holding. That said it doesn't alter the point of the problem which is Why the Design was altered by Estes some years back eliminating the Stick landing gear.

There are a couple things that can be done to help with these. First and most important is to Add at least a 1" diameter spill hole in the Parasheet... Plastic or Nylon makes NO difference. Depending on your models finished mass it might require a bit larger opening to dampen out the chute Oscillation thereby lessening the landing force exerted on the stick legs.

2nd is to wrap the landing legs with a wrap or two of computer paper & white or yellow glue. I laminated the entire legs before adding the centering rings in your case this won't be possible. Wrapping them as high up as you can will greatly strengthen each.

3rd would be to add a clear epoxy fillet to the Fin/cardstock joints, Won't look quite as pretty unless you repaint the model, but will greatly lessen the seperation potential particularly if you use the epoxy rivet method on the cardstock/fin sides.

Hope this suggestions help.

[masterblaster]

All, the suggestion are awesome this is what I was hopeing to learn from! The model was purchased from Qmodeling (which I believe they are still not up and running). Micromeister, your suggestion is perfect for the landing gear and parashoot recovery, the launch when up great for whatever reason the shoot came out but didnt want to open all the way, thus a broken landing gear stick. So I think I'll push the rod back (spring coiled on this one) , carve out the disk and replace it with a new one with some reinforced computer paper.

[JAL3]

All, the suggestion are awesome this is what I was hopeing to learn from! The model was purchased from Qmodeling (which I believe they are still not up and running). Micromeister, your suggestion is perfect for the landing gear and parashoot recovery, the launch when up great for whatever reason the shoot came out but didnt want to open all the way, thus a broken landing gear stick. So I think I'll push the rod back (spring coiled on this one) , carve out the disk and replace it with a new one with some reinforced computer paper.

If its QModelling then yours is an upscale, isn't it?

[masterblaster]

If its QModelling then yours is an upscale, isn't it?

Yes. it's just about 4ft tall. The landing gear has a spring suspension which I thought was really cool!

[Rocket_Man]

PARASHEET is a PARACHUTE !!! LOL !!!

[Micromeister]

Rocket_Man:
Just so you know the Difference:
Parasheets & Parachutes while somewhat similar at first glance, that is they both dramatically reduce the decent rate of a falling object, However do so with some very different characteristics.

Parasheets are simple to construct, cut from a single flat piece of material in whatever form is desired. be it X-form, Hex, Octagonal or what-have-you. While they catch air they do not empty or dispures it as real Hemisphere Parachutes do.

Parachutes are built from gores in any number combination usually 6 and up with a top center spill hole specifically sized to help stablize the unit eliminating the vast majority of oscillation during decent. These Gores are sewn into a hemispheral domed canopy for a given air handling volumn.

Parasheet perform our recovery task OK, but are subject to increasing rotational oscillation as the Non-porous canopy material(s) dumps air from beneath in a rock-rotating motion on the way down. This Oscillation can and does cause considerable landing damage to fins and lower extended parts if not dampened out by adding a spill hole at the apex of the parasheet canopy.

Hope this help in seeing the important difference between the two recovery devices.

[masterblaster]

I honestly didnt know the difference thanks for clarification.
So in regards to the size of a spill hole. I'm quessing it's a combination of weight of rocket and size of parasheet?
Perhaps once I've completed the landing gear, I'll need to hop over to the recovery post.

[mkadams001]

Micro...are you making this up with the parasheet vs parachute definition?

[Micromeister]

mkadams001:
I do not "make stuff Up". Difference between the two are as stated. Basicly Parasheets are cut from a single Flat material with shrould lines connected at the corners-4 and Up. Usually non-porus sheet plastic, mylar, or rip-stop nylon. Most of us commonly refer to our Parasheets as "Chutes" in conversation, but there is a difference.

Masterblaster:
Actually the spill hole is determinded by a combination of overall volumn & diameter of the Chute. I don't have the calculation handy here but It's easily found on-line.

Sandman:
How was the Parasheet/Paraschute explaination rude? I REALLY do not understand. If obvious errors in thinking are not pointed out with explaination...HOW can we learn? There was/is no ill-will intended. If I somehow offended, I do apologize.

[troj]

Reading this, I don't think Micro had any intention of being rude, but was rather trying to clarify a bit.

As for the terminology, yes, technically a "parasheet" doesn't exist, but it's a term he's using to differentiate between a parachute made from a single, flat piece of material, versus one made from shaped gores that are then joined (typically sewn) together. In that regard, it's a handy single term to identify how the parachute is constructed.

-Kevin

[masterblaster]

Well, I've got the rod out! I'm feeling more optimistic now.

[mkadams001]

I do not think that there is any rudeness here at all. My opinion differs in that a parasheet is a type of parachute therefore, the term parachute would be accurate and not a term of convenience .

In addition to a spill hole, lengthening the shroud lines will help stability as well. I have also made a 30" chute with 16 shroud lines and that helped stability with the added benefit of being really cool looking with open.

[Micromeister]

[QUOTE=troj;377501]Reading this, I don't think Micro had any intention of being rude, but was rather trying to clarify a bit.

As for the terminology, yes, technically a "parasheet" doesn't exist, but it's a term he's using to differentiate between a parachute made from a single, flat piece of material, versus one made from shaped gores that are then joined (typically sewn) together. In that regard, it's a handy single term to identify how the parachute is constructed.



Kevin & mkadams001:
As mentioned I do NOT make this stuff up!

Kevin I'm not sure why you'd state the term "Parasheet" does not exist as it's been in common use since I started building and flying Model Rockets in the 1960's. I first learned the term while reading my new copy of G. Harry Stine's Handbook of Model Rocketry second edition in the early 60's. The Terms Parachute and Parasheet were explained in depth with both text and drawings. These writings have been passed on with each additional edition i've had the pleasure of reading including the current 7th edition on pages 180-181 with very nice (and OLD) hand drawn Graphics in Figure 12-7 and 12-8 on page 182.

Parasheet is the correct term and a very objective view of their construction and workings consistantly used in Model Rocketry since the early days...perhaps not as common in the HPR community but a legitimate term none the less. ie All Parasheets are a form of Parachute, however not all Parachutes are Parasheets. The Rather large difference in performance and decent characteristics have been touched on.

mkadams is correct in that adding length to our shroudlines will to a degree help stabilize our canopy recovery devices. Many current Mod-Roc competition flyers regularly use 1/4mil mylar chutes with 8,12 & 16 shrouds at least 1-1/2 to 3 time the diameter in sizes 18" to 48". They are indeed pretty nifty to watch waft down lowering a few gram model body...or Thermal away on an updraft.

[Micromeister]

Very Nicely done masterblaster!
now they can be reinforced the entire length of the Dowel shaft which should greatly help with longevity

[masterblaster]

Very Nicely done masterblaster!
now the can reinforce the entire length of the Dowel shaft which should greatly help with longevity

Thanks!